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#11
07-02-2010, 09:38 AM
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the people who flew these planes in real life, not in a test situation, are biased, even most of them couldn't know what the plane is really capable of, there's too many variables to take into account for them to know...
the factory specs are the closest things we have to an idea of what a plane could do, because the plane tested is perfectly built and tuned, and it being tested in a controlled environment, with tests specifically designed to push the plane to its limits. just a close idea... not the actual thing the plane can do, but the theoretical limits, assuming all the variables are right, it might be achievable, and that's a lot closer than what a few pilots here or there who were hopped up on adrenaline, fighting for their lives, without a geforce guage, and probly not paying too close attention to the speed of their plane could remember. as to how one plane should fight another... thats all situation dependant, you cant say throttling back is always nessisary to stay behind, but u can't say you'll stay behind your target if u don't... it depends on how fast your target is moving, how good of a pilot your target is, etc... just so many variables... Last edited by AKA_Tenn; 07-02-2010 at 09:57 AM. 
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#12
07-02-2010, 11:34 AM
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I won't enter the aircraft performace argument, but surely whether an aircraft is 'propelled' or 'tracted' is irrelevant. Newton's Third Law doesn't care whether the engine is located in front of, or aft of, the center of mass of the aircraft. I think. Unless you're referring to the difference propwash over the wings / fuselage makes.
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#13
07-02-2010, 01:44 PM
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FM whining -- posts that start 'objective' and 'mathematical' in the first 30% and finish in flaming and hatred in the last 70%. I have seen thousands of those in the last seven years. Thousands.
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#14
07-02-2010, 03:56 PM
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Sounds pretty anecdotal to me...
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#15
07-02-2010, 07:24 PM
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When confronted with an actual test made in 1989, by actual experimental test pilots (who were conditionned by jet experience to make dubious conclusions about the low-speed performance end, because they could not risk testing it on such valuable aircrafts), mathematics failed utterly to make an even ballpark prediction... (I mistakenly said the disparity was 64 MPH: It was 56 MPH: 300 MPH IAS was the actual P-51D "Corner Speed" vs the "math" of 2.44 X stall speed, which gives about 244 MPH IAS...) Maximum level speed of the P-51D at METO, at 10 000 ft. is about 315 MPH IAS... Thus 300 MPH IAS is "very close" to that... Math theory completely fails to account for power output from the propeller TRACTION to load up the wing's lift, and thus delay the "Corner Speed" 56 MPH higher at METO... The wing's lift is not significantly loaded up by PROPULSION thrust: I can link a crude graphic that explains why lifting a nose devoid of traction is obviously less taxing for the winglift than one loaded with traction... METO is equivalent in WWII to "Normal Power", or the maximum power without time limit. At WEP which is more often discussed for WWII fighters, It could very well be the "Corner Speed" would then be delayed up to 340-360 MPH IAS, or up to 120 MPH higher than math deductions say... Tractive power has leverage on the winglift, while winglift has leverage on propulsion... That this is ignored shows just how unstudied basic WWII fighter performance is by post-war math: This explains the importance of downthrottling to which post-war math theory is totally oblivious... Basically, more prop power means more wingloading in a turn... Hence a full power Spit is "heavier" on its wings than a downthrottled FW-190A: http://img30.imageshack.us/img30/471...sononfw190.jpg Gaston
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#16
07-02-2010, 07:32 PM
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#17
07-02-2010, 08:07 PM
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Spiralling down for the pursued, in WWII, is also often a bad idea, since if he wins the turn contest like this, he will be far too low to raise his nose to fire above himself at the former pursuer... This is why WWII turning contests tend to be horizontal, and a pursued aircraft will spiral down only to compensate the fact that it can't compete in turns with the pursuer: This surrendering of the "high ground" by the pursued usually only delays the inevitable, unless he is lucky... None of this is of great importance to jets where only speed matters... It is very clear that "energy-management" tactics like high or low "yoyos" are very rare in WWII, quick short-term downthrottling being more common to avoid overunning... (This is clearly very different from what happens in the link below...) Second, it is clear that the P-51D in this case did not have excess speed: He was being gained on in the turn from behind!: http://www.spitfireperformance.com/m...an-24may44.jpg The purpose of downthrottling in this case is obviously to increase the sustained turn rate by reducing its turning radius... Or just reducing the turn radius... Unlike jets, props do not need more airspeed going into the intakes to generate more power at the rear: On prop/piston aircrafts, the slower they go the more power they have, and this acts as a "floor" that prevents stalling in sustained turns, but it tightens the radius a lot by relieving the traction power off the wings... The piston/prop "energy" is thus mostly dependent on the engine, and too much power on a powerful prop engine will pull you out of your tight sustained turn.... On a jet, the turn will be tighter with more speed until you reach the "Corner Speed". These WWII prop aircrafts tended to promote prolonged sustained level turn fighting, unless one side often had the height advantage (Me-109 Eastern Front), a centralised armament that could hit in a concentrated way over a great range of distances: A fast closure brings the target closer rapidly: Me-109 and P-38... Or a very flammable target, as the fast closure rate of Boom and Zoom allows only a brief hit: Japanese aircrafts... As the actual combat example I linked demonstrates (being on the deck over multiple 360°s, it elliminates all variables), Piston/prop traction power requires completely different thinking from what jets do: The combat knowledge in one area is utterly inapplicable to the other, which is something I am sure post-war theorists like Shaw failed to recognize... Gaston Last edited by Gaston; 07-02-2010 at 08:43 PM.
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#18
07-02-2010, 08:23 PM
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Sorry we posted at the same time. Your description is exactly correct: This does not happen to the same extent at all on jet propulsion because the wing's lift center is leading the way, and propulsion is not dragging it but pushing it. There is also the added element of the propeller disc being a broader more stable surface, while the jet propulsion stream is narrower. Finally, radial engine propeller aircrafts tend to have a shorter nose, which seems to reduce the "leverage" of the propeller to make things want to go straight, which might explain the slow-speed turn performance of the FW-190A (much superior to the FW-190D according to its pilots). Note also La-5 vs lagg-3, or Ki-100 vs Ki-61: Large unexpected jumps in turn maneuverability: In both cases the radial version was heavier... Gaston Last edited by Gaston; 07-02-2010 at 08:28 PM.
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#19
07-02-2010, 11:37 PM
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